The present invention relates to a hand-held washer for beads or to a plurality of containers such as test tubes or multiwell trays and, more particularly, to a hand-held washer for beads, tubes or multiwell trays that is convenient, easy, and effective to use.
Multiwell trays are typically made of molded plastic and have a number of wells in a row and column array. Each well is analogous to a small test tube. For example, a popular multiwell tray is the microplate (also known as a micro-titer or micro-test plate) which has 96 wells in an 8 row by 12 column array.
In various tests or assays, such as an immunoassay test, the exterior surfaces of beads or the interior surfaces of tubes or wells are known as the solid phase. A substance, usually a protein, is physically or chemically attached or bound to the solid phase. This protein has the capability of reacting with or binding to certain other substances. Liquid or suspended chemical reactants are added in a particular sequence such that each will bind to a predecessor if present. This continuation will result in a measurable change in the color of the solution. After the addition of each reactant, the well must be washed or diluted to the extent that only the reactants bound to the solid phase or sandwiched to other bound reactants will remain. (Beads are usually placed within a tube or well to be washed.)
Various problems have arisen with presently available assay washers. Since all presently available assay washers are opaque, bubble or fluid blockage can readily occur in the channels and tubes of the washer without it being detected so that the effective and efficient washing of the solid phase is impeded. Moreover, presently designed hand-held washers do not permit the operator readily to see into the microplate wells to monitor the washing process. Additionally, the tubes projecting from many of these previous washers either scratch the interior of the tubes or wells or, to avoid scratching, are positioned so that they do not touch the bottoms of the tubes or wells, preventing the contents of the tube or well from being completely removed. Accordingly, there is a significant, unmet need for a hand-held washer that efficiently and effectively washes beads, tubes or the wells of a multiwell tray such as a microplate.